Cannulae have a wide variety of applications during surgical procedures. For example, in coronary surgery, venous and arterial cannulae are used to conduct fluids such as blood between the body and bypass equipment. Cannulae are used to conduct cardioplegia solution for both antigrade and retrograde solution administration, and cannulae are also used as vents, sumps, and for chest tube fluid suction.
A recent trend in surgical procedures, such as cardiopulmonary bypasses, is to utilize a kinetically assisted venous drainage system, such as that sold as The Resting Heart™ System by Medtronic and described in U.S. Patent Application Publication 2005/63860, the content of which is hereby incorporated by reference. Such a system increases suction on the drainage cannula relative to traditional vacuum assisted venous drainage and gravity venous drainage systems. Such increased suction may cause the fluid inlets to come into contact with and be occluded by surrounding tissue, thereby reducing fluid flow.